/* ** $Id: lcode.c,v 2.112.1.1 2017/04/19 17:20:42 roberto Exp $ ** Code generator for Lua ** See Copyright Notice in lua.h */ #define lcode_c #define LUA_CORE #include "lprefix.h" #include #include #include "lua.h" #include "lcode.h" #include "ldebug.h" #include "ldo.h" #include "lgc.h" #include "llex.h" #include "lmem.h" #include "lobject.h" #include "lopcodes.h" #include "lparser.h" #include "lstring.h" #include "ltable.h" #include "lvm.h" /* Maximum number of registers in a Lua function (must fit in 8 bits) */ #define MAXREGS 255 #define hasjumps(e) ((e)->t != (e)->f) /* ** If expression is a numeric constant, fills 'v' with its value ** and returns 1. Otherwise, returns 0. */ static int tonumeral(const expdesc *e, TValue *v) { if (hasjumps(e)) return 0; /* not a numeral */ switch (e->k) { case VKINT: if (v) setivalue(v, e->u.ival); return 1; case VKFLT: if (v) setfltvalue(v, e->u.nval); return 1; default: return 0; } } /* ** Create a OP_LOADNIL instruction, but try to optimize: if the previous ** instruction is also OP_LOADNIL and ranges are compatible, adjust ** range of previous instruction instead of emitting a new one. (For ** instance, 'local a; local b' will generate a single opcode.) */ void luaK_nil (FuncState *fs, int from, int n) { Instruction *previous; int l = from + n - 1; /* last register to set nil */ if (fs->pc > fs->lasttarget) { /* no jumps to current position? */ previous = &fs->f->code[fs->pc-1]; if (GET_OPCODE(*previous) == OP_LOADNIL) { /* previous is LOADNIL? */ int pfrom = GETARG_A(*previous); /* get previous range */ int pl = pfrom + GETARG_B(*previous); if ((pfrom <= from && from <= pl + 1) || (from <= pfrom && pfrom <= l + 1)) { /* can connect both? */ if (pfrom < from) from = pfrom; /* from = min(from, pfrom) */ if (pl > l) l = pl; /* l = max(l, pl) */ SETARG_A(*previous, from); SETARG_B(*previous, l - from); return; } } /* else go through */ } luaK_codeABC(fs, OP_LOADNIL, from, n - 1, 0); /* else no optimization */ } /* ** Gets the destination address of a jump instruction. Used to traverse ** a list of jumps. */ static int getjump (FuncState *fs, int pc) { int offset = GETARG_sBx(fs->f->code[pc]); if (offset == NO_JUMP) /* point to itself represents end of list */ return NO_JUMP; /* end of list */ else return (pc+1)+offset; /* turn offset into absolute position */ } /* ** Fix jump instruction at position 'pc' to jump to 'dest'. ** (Jump addresses are relative in Lua) */ static void fixjump (FuncState *fs, int pc, int dest) { Instruction *jmp = &fs->f->code[pc]; int offset = dest - (pc + 1); lua_assert(dest != NO_JUMP); if (abs(offset) > MAXARG_sBx) luaX_syntaxerror(fs->ls, "control structure too long"); SETARG_sBx(*jmp, offset); } /* ** Concatenate jump-list 'l2' into jump-list 'l1' */ void luaK_concat (FuncState *fs, int *l1, int l2) { if (l2 == NO_JUMP) return; /* nothing to concatenate? */ else if (*l1 == NO_JUMP) /* no original list? */ *l1 = l2; /* 'l1' points to 'l2' */ else { int list = *l1; int next; while ((next = getjump(fs, list)) != NO_JUMP) /* find last element */ list = next; fixjump(fs, list, l2); /* last element links to 'l2' */ } } /* ** Create a jump instruction and return its position, so its destination ** can be fixed later (with 'fixjump'). If there are jumps to ** this position (kept in 'jpc'), link them all together so that ** 'patchlistaux' will fix all them directly to the final destination. */ int luaK_jump (FuncState *fs) { int jpc = fs->jpc; /* save list of jumps to here */ int j; fs->jpc = NO_JUMP; /* no more jumps to here */ j = luaK_codeAsBx(fs, OP_JMP, 0, NO_JUMP); luaK_concat(fs, &j, jpc); /* keep them on hold */ return j; } /* ** Code a 'return' instruction */ void luaK_ret (FuncState *fs, int first, int nret) { luaK_codeABC(fs, OP_RETURN, first, nret+1, 0); } /* ** Code a "conditional jump", that is, a test or comparison opcode ** followed by a jump. Return jump position. */ static int condjump (FuncState *fs, OpCode op, int A, int B, int C) { luaK_codeABC(fs, op, A, B, C); return luaK_jump(fs); } /* ** returns current 'pc' and marks it as a jump target (to avoid wrong ** optimizations with consecutive instructions not in the same basic block). */ int luaK_getlabel (FuncState *fs) { fs->lasttarget = fs->pc; return fs->pc; } /* ** Returns the position of the instruction "controlling" a given ** jump (that is, its condition), or the jump itself if it is ** unconditional. */ static Instruction *getjumpcontrol (FuncState *fs, int pc) { Instruction *pi = &fs->f->code[pc]; if (pc >= 1 && testTMode(GET_OPCODE(*(pi-1)))) return pi-1; else return pi; } /* ** Patch destination register for a TESTSET instruction. ** If instruction in position 'node' is not a TESTSET, return 0 ("fails"). ** Otherwise, if 'reg' is not 'NO_REG', set it as the destination ** register. Otherwise, change instruction to a simple 'TEST' (produces ** no register value) */ static int patchtestreg (FuncState *fs, int node, int reg) { Instruction *i = getjumpcontrol(fs, node); if (GET_OPCODE(*i) != OP_TESTSET) return 0; /* cannot patch other instructions */ if (reg != NO_REG && reg != GETARG_B(*i)) SETARG_A(*i, reg); else { /* no register to put value or register already has the value; change instruction to simple test */ *i = CREATE_ABC(OP_TEST, GETARG_B(*i), 0, GETARG_C(*i)); } return 1; } /* ** Traverse a list of tests ensuring no one produces a value */ static void removevalues (FuncState *fs, int list) { for (; list != NO_JUMP; list = getjump(fs, list)) patchtestreg(fs, list, NO_REG); } /* ** Traverse a list of tests, patching their destination address and ** registers: tests producing values jump to 'vtarget' (and put their ** values in 'reg'), other tests jump to 'dtarget'. */ static void patchlistaux (FuncState *fs, int list, int vtarget, int reg, int dtarget) { while (list != NO_JUMP) { int next = getjump(fs, list); if (patchtestreg(fs, list, reg)) fixjump(fs, list, vtarget); else fixjump(fs, list, dtarget); /* jump to default target */ list = next; } } /* ** Ensure all pending jumps to current position are fixed (jumping ** to current position with no values) and reset list of pending ** jumps */ static void dischargejpc (FuncState *fs) { patchlistaux(fs, fs->jpc, fs->pc, NO_REG, fs->pc); fs->jpc = NO_JUMP; } /* ** Add elements in 'list' to list of pending jumps to "here" ** (current position) */ void luaK_patchtohere (FuncState *fs, int list) { luaK_getlabel(fs); /* mark "here" as a jump target */ luaK_concat(fs, &fs->jpc, list); } /* ** Path all jumps in 'list' to jump to 'target'. ** (The assert means that we cannot fix a jump to a forward address ** because we only know addresses once code is generated.) */ void luaK_patchlist (FuncState *fs, int list, int target) { if (target == fs->pc) /* 'target' is current position? */ luaK_patchtohere(fs, list); /* add list to pending jumps */ else { lua_assert(target < fs->pc); patchlistaux(fs, list, target, NO_REG, target); } } /* ** Path all jumps in 'list' to close upvalues up to given 'level' ** (The assertion checks that jumps either were closing nothing ** or were closing higher levels, from inner blocks.) */ void luaK_patchclose (FuncState *fs, int list, int level) { level++; /* argument is +1 to reserve 0 as non-op */ for (; list != NO_JUMP; list = getjump(fs, list)) { lua_assert(GET_OPCODE(fs->f->code[list]) == OP_JMP && (GETARG_A(fs->f->code[list]) == 0 || GETARG_A(fs->f->code[list]) >= level)); SETARG_A(fs->f->code[list], level); } } /* ** Emit instruction 'i', checking for array sizes and saving also its ** line information. Return 'i' position. */ static int luaK_code (FuncState *fs, Instruction i) { Proto *f = fs->f; dischargejpc(fs); /* 'pc' will change */ /* put new instruction in code array */ luaM_growvector(fs->ls->L, f->code, fs->pc, f->sizecode, Instruction, MAX_INT, "opcodes"); f->code[fs->pc] = i; /* save corresponding line information */ luaM_growvector(fs->ls->L, f->lineinfo, fs->pc, f->sizelineinfo, int, MAX_INT, "opcodes"); f->lineinfo[fs->pc] = fs->ls->lastline; return fs->pc++; } /* ** Format and emit an 'iABC' instruction. (Assertions check consistency ** of parameters versus opcode.) */ int luaK_codeABC (FuncState *fs, OpCode o, int a, int b, int c) { lua_assert(getOpMode(o) == iABC); lua_assert(getBMode(o) != OpArgN || b == 0); lua_assert(getCMode(o) != OpArgN || c == 0); lua_assert(a <= MAXARG_A && b <= MAXARG_B && c <= MAXARG_C); return luaK_code(fs, CREATE_ABC(o, a, b, c)); } /* ** Format and emit an 'iABx' instruction. */ int luaK_codeABx (FuncState *fs, OpCode o, int a, unsigned int bc) { lua_assert(getOpMode(o) == iABx || getOpMode(o) == iAsBx); lua_assert(getCMode(o) == OpArgN); lua_assert(a <= MAXARG_A && bc <= MAXARG_Bx); return luaK_code(fs, CREATE_ABx(o, a, bc)); } /* ** Emit an "extra argument" instruction (format 'iAx') */ static int codeextraarg (FuncState *fs, int a) { lua_assert(a <= MAXARG_Ax); return luaK_code(fs, CREATE_Ax(OP_EXTRAARG, a)); } /* ** Emit a "load constant" instruction, using either 'OP_LOADK' ** (if constant index 'k' fits in 18 bits) or an 'OP_LOADKX' ** instruction with "extra argument". */ int luaK_codek (FuncState *fs, int reg, int k) { if (k <= MAXARG_Bx) return luaK_codeABx(fs, OP_LOADK, reg, k); else { int p = luaK_codeABx(fs, OP_LOADKX, reg, 0); codeextraarg(fs, k); return p; } } /* ** Check register-stack level, keeping track of its maximum size ** in field 'maxstacksize' */ void luaK_checkstack (FuncState *fs, int n) { int newstack = fs->freereg + n; if (newstack > fs->f->maxstacksize) { if (newstack >= MAXREGS) luaX_syntaxerror(fs->ls, "function or expression needs too many registers"); fs->f->maxstacksize = cast_byte(newstack); } } /* ** Reserve 'n' registers in register stack */ void luaK_reserveregs (FuncState *fs, int n) { luaK_checkstack(fs, n); fs->freereg += n; } /* ** Free register 'reg', if it is neither a constant index nor ** a local variable. ) */ static void freereg (FuncState *fs, int reg) { if (!ISK(reg) && reg >= fs->nactvar) { fs->freereg--; lua_assert(reg == fs->freereg); } } /* ** Free register used by expression 'e' (if any) */ static void freeexp (FuncState *fs, expdesc *e) { if (e->k == VNONRELOC) freereg(fs, e->u.info); } /* ** Free registers used by expressions 'e1' and 'e2' (if any) in proper ** order. */ static void freeexps (FuncState *fs, expdesc *e1, expdesc *e2) { int r1 = (e1->k == VNONRELOC) ? e1->u.info : -1; int r2 = (e2->k == VNONRELOC) ? e2->u.info : -1; if (r1 > r2) { freereg(fs, r1); freereg(fs, r2); } else { freereg(fs, r2); freereg(fs, r1); } } /* ** Add constant 'v' to prototype's list of constants (field 'k'). ** Use scanner's table to cache position of constants in constant list ** and try to reuse constants. Because some values should not be used ** as keys (nil cannot be a key, integer keys can collapse with float ** keys), the caller must provide a useful 'key' for indexing the cache. */ static int addk (FuncState *fs, TValue *key, TValue *v) { lua_State *L = fs->ls->L; Proto *f = fs->f; TValue *idx = luaH_set(L, fs->ls->h, key); /* index scanner table */ int k, oldsize; if (ttisinteger(idx)) { /* is there an index there? */ k = cast_int(ivalue(idx)); /* correct value? (warning: must distinguish floats from integers!) */ if (k < fs->nk && ttype(&f->k[k]) == ttype(v) && luaV_rawequalobj(&f->k[k], v)) return k; /* reuse index */ } /* constant not found; create a new entry */ oldsize = f->sizek; k = fs->nk; /* numerical value does not need GC barrier; table has no metatable, so it does not need to invalidate cache */ setivalue(idx, k); luaM_growvector(L, f->k, k, f->sizek, TValue, MAXARG_Ax, "constants"); while (oldsize < f->sizek) setnilvalue(&f->k[oldsize++]); setobj(L, &f->k[k], v); fs->nk++; luaC_barrier(L, f, v); return k; } /* ** Add a string to list of constants and return its index. */ int luaK_stringK (FuncState *fs, TString *s) { TValue o; setsvalue(fs->ls->L, &o, s); return addk(fs, &o, &o); /* use string itself as key */ } /* ** Add an integer to list of constants and return its index. ** Integers use userdata as keys to avoid collision with floats with ** same value; conversion to 'void*' is used only for hashing, so there ** are no "precision" problems. */ int luaK_intK (FuncState *fs, lua_Integer n) { TValue k, o; setpvalue(&k, cast(void*, cast(size_t, n))); setivalue(&o, n); return addk(fs, &k, &o); } /* ** Add a float to list of constants and return its index. */ static int luaK_numberK (FuncState *fs, lua_Number r) { TValue o; setfltvalue(&o, r); return addk(fs, &o, &o); /* use number itself as key */ } /* ** Add a boolean to list of constants and return its index. */ static int boolK (FuncState *fs, int b) { TValue o; setbvalue(&o, b); return addk(fs, &o, &o); /* use boolean itself as key */ } /* ** Add nil to list of constants and return its index. */ static int nilK (FuncState *fs) { TValue k, v; setnilvalue(&v); /* cannot use nil as key; instead use table itself to represent nil */ sethvalue(fs->ls->L, &k, fs->ls->h); return addk(fs, &k, &v); } /* ** Fix an expression to return the number of results 'nresults'. ** Either 'e' is a multi-ret expression (function call or vararg) ** or 'nresults' is LUA_MULTRET (as any expression can satisfy that). */ void luaK_setreturns (FuncState *fs, expdesc *e, int nresults) { if (e->k == VCALL) { /* expression is an open function call? */ SETARG_C(getinstruction(fs, e), nresults + 1); } else if (e->k == VVARARG) { Instruction *pc = &getinstruction(fs, e); SETARG_B(*pc, nresults + 1); SETARG_A(*pc, fs->freereg); luaK_reserveregs(fs, 1); } else lua_assert(nresults == LUA_MULTRET); } /* ** Fix an expression to return one result. ** If expression is not a multi-ret expression (function call or ** vararg), it already returns one result, so nothing needs to be done. ** Function calls become VNONRELOC expressions (as its result comes ** fixed in the base register of the call), while vararg expressions ** become VRELOCABLE (as OP_VARARG puts its results where it wants). ** (Calls are created returning one result, so that does not need ** to be fixed.) */ void luaK_setoneret (FuncState *fs, expdesc *e) { if (e->k == VCALL) { /* expression is an open function call? */ /* already returns 1 value */ lua_assert(GETARG_C(getinstruction(fs, e)) == 2); e->k = VNONRELOC; /* result has fixed position */ e->u.info = GETARG_A(getinstruction(fs, e)); } else if (e->k == VVARARG) { SETARG_B(getinstruction(fs, e), 2); e->k = VRELOCABLE; /* can relocate its simple result */ } } /* ** Ensure that expression 'e' is not a variable. */ void luaK_dischargevars (FuncState *fs, expdesc *e) { switch (e->k) { case VLOCAL: { /* already in a register */ e->k = VNONRELOC; /* becomes a non-relocatable value */ break; } case VUPVAL: { /* move value to some (pending) register */ e->u.info = luaK_codeABC(fs, OP_GETUPVAL, 0, e->u.info, 0); e->k = VRELOCABLE; break; } case VINDEXED: { OpCode op; freereg(fs, e->u.ind.idx); if (e->u.ind.vt == VLOCAL) { /* is 't' in a register? */ freereg(fs, e->u.ind.t); op = OP_GETTABLE; } else { lua_assert(e->u.ind.vt == VUPVAL); op = OP_GETTABUP; /* 't' is in an upvalue */ } e->u.info = luaK_codeABC(fs, op, 0, e->u.ind.t, e->u.ind.idx); e->k = VRELOCABLE; break; } case VVARARG: case VCALL: { luaK_setoneret(fs, e); break; } default: break; /* there is one value available (somewhere) */ } } /* ** Ensures expression value is in register 'reg' (and therefore ** 'e' will become a non-relocatable expression). */ static void discharge2reg (FuncState *fs, expdesc *e, int reg) { luaK_dischargevars(fs, e); switch (e->k) { case VNIL: { luaK_nil(fs, reg, 1); break; } case VFALSE: case VTRUE: { luaK_codeABC(fs, OP_LOADBOOL, reg, e->k == VTRUE, 0); break; } case VK: { luaK_codek(fs, reg, e->u.info); break; } case VKFLT: { luaK_codek(fs, reg, luaK_numberK(fs, e->u.nval)); break; } case VKINT: { luaK_codek(fs, reg, luaK_intK(fs, e->u.ival)); break; } case VRELOCABLE: { Instruction *pc = &getinstruction(fs, e); SETARG_A(*pc, reg); /* instruction will put result in 'reg' */ break; } case VNONRELOC: { if (reg != e->u.info) luaK_codeABC(fs, OP_MOVE, reg, e->u.info, 0); break; } default: { lua_assert(e->k == VJMP); return; /* nothing to do... */ } } e->u.info = reg; e->k = VNONRELOC; } /* ** Ensures expression value is in any register. */ static void discharge2anyreg (FuncState *fs, expdesc *e) { if (e->k != VNONRELOC) { /* no fixed register yet? */ luaK_reserveregs(fs, 1); /* get a register */ discharge2reg(fs, e, fs->freereg-1); /* put value there */ } } static int code_loadbool (FuncState *fs, int A, int b, int jump) { luaK_getlabel(fs); /* those instructions may be jump targets */ return luaK_codeABC(fs, OP_LOADBOOL, A, b, jump); } /* ** check whether list has any jump that do not produce a value ** or produce an inverted value */ static int need_value (FuncState *fs, int list) { for (; list != NO_JUMP; list = getjump(fs, list)) { Instruction i = *getjumpcontrol(fs, list); if (GET_OPCODE(i) != OP_TESTSET) return 1; } return 0; /* not found */ } /* ** Ensures final expression result (including results from its jump ** lists) is in register 'reg'. ** If expression has jumps, need to patch these jumps either to ** its final position or to "load" instructions (for those tests ** that do not produce values). */ static void exp2reg (FuncState *fs, expdesc *e, int reg) { discharge2reg(fs, e, reg); if (e->k == VJMP) /* expression itself is a test? */ luaK_concat(fs, &e->t, e->u.info); /* put this jump in 't' list */ if (hasjumps(e)) { int final; /* position after whole expression */ int p_f = NO_JUMP; /* position of an eventual LOAD false */ int p_t = NO_JUMP; /* position of an eventual LOAD true */ if (need_value(fs, e->t) || need_value(fs, e->f)) { int fj = (e->k == VJMP) ? NO_JUMP : luaK_jump(fs); p_f = code_loadbool(fs, reg, 0, 1); p_t = code_loadbool(fs, reg, 1, 0); luaK_patchtohere(fs, fj); } final = luaK_getlabel(fs); patchlistaux(fs, e->f, final, reg, p_f); patchlistaux(fs, e->t, final, reg, p_t); } e->f = e->t = NO_JUMP; e->u.info = reg; e->k = VNONRELOC; } /* ** Ensures final expression result (including results from its jump ** lists) is in next available register. */ void luaK_exp2nextreg (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); freeexp(fs, e); luaK_reserveregs(fs, 1); exp2reg(fs, e, fs->freereg - 1); } /* ** Ensures final expression result (including results from its jump ** lists) is in some (any) register and return that register. */ int luaK_exp2anyreg (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); if (e->k == VNONRELOC) { /* expression already has a register? */ if (!hasjumps(e)) /* no jumps? */ return e->u.info; /* result is already in a register */ if (e->u.info >= fs->nactvar) { /* reg. is not a local? */ exp2reg(fs, e, e->u.info); /* put final result in it */ return e->u.info; } } luaK_exp2nextreg(fs, e); /* otherwise, use next available register */ return e->u.info; } /* ** Ensures final expression result is either in a register or in an ** upvalue. */ void luaK_exp2anyregup (FuncState *fs, expdesc *e) { if (e->k != VUPVAL || hasjumps(e)) luaK_exp2anyreg(fs, e); } /* ** Ensures final expression result is either in a register or it is ** a constant. */ void luaK_exp2val (FuncState *fs, expdesc *e) { if (hasjumps(e)) luaK_exp2anyreg(fs, e); else luaK_dischargevars(fs, e); } /* ** Ensures final expression result is in a valid R/K index ** (that is, it is either in a register or in 'k' with an index ** in the range of R/K indices). ** Returns R/K index. */ int luaK_exp2RK (FuncState *fs, expdesc *e) { luaK_exp2val(fs, e); switch (e->k) { /* move constants to 'k' */ case VTRUE: e->u.info = boolK(fs, 1); goto vk; case VFALSE: e->u.info = boolK(fs, 0); goto vk; case VNIL: e->u.info = nilK(fs); goto vk; case VKINT: e->u.info = luaK_intK(fs, e->u.ival); goto vk; case VKFLT: e->u.info = luaK_numberK(fs, e->u.nval); goto vk; case VK: vk: e->k = VK; if (e->u.info <= MAXINDEXRK) /* constant fits in 'argC'? */ return RKASK(e->u.info); else break; default: break; } /* not a constant in the right range: put it in a register */ return luaK_exp2anyreg(fs, e); } /* ** Generate code to store result of expression 'ex' into variable 'var'. */ void luaK_storevar (FuncState *fs, expdesc *var, expdesc *ex) { switch (var->k) { case VLOCAL: { freeexp(fs, ex); exp2reg(fs, ex, var->u.info); /* compute 'ex' into proper place */ return; } case VUPVAL: { int e = luaK_exp2anyreg(fs, ex); luaK_codeABC(fs, OP_SETUPVAL, e, var->u.info, 0); break; } case VINDEXED: { OpCode op = (var->u.ind.vt == VLOCAL) ? OP_SETTABLE : OP_SETTABUP; int e = luaK_exp2RK(fs, ex); luaK_codeABC(fs, op, var->u.ind.t, var->u.ind.idx, e); break; } default: lua_assert(0); /* invalid var kind to store */ } freeexp(fs, ex); } /* ** Emit SELF instruction (convert expression 'e' into 'e:key(e,'). */ void luaK_self (FuncState *fs, expdesc *e, expdesc *key) { int ereg; luaK_exp2anyreg(fs, e); ereg = e->u.info; /* register where 'e' was placed */ freeexp(fs, e); e->u.info = fs->freereg; /* base register for op_self */ e->k = VNONRELOC; /* self expression has a fixed register */ luaK_reserveregs(fs, 2); /* function and 'self' produced by op_self */ luaK_codeABC(fs, OP_SELF, e->u.info, ereg, luaK_exp2RK(fs, key)); freeexp(fs, key); } /* ** Negate condition 'e' (where 'e' is a comparison). */ static void negatecondition (FuncState *fs, expdesc *e) { Instruction *pc = getjumpcontrol(fs, e->u.info); lua_assert(testTMode(GET_OPCODE(*pc)) && GET_OPCODE(*pc) != OP_TESTSET && GET_OPCODE(*pc) != OP_TEST); SETARG_A(*pc, !(GETARG_A(*pc))); } /* ** Emit instruction to jump if 'e' is 'cond' (that is, if 'cond' ** is true, code will jump if 'e' is true.) Return jump position. ** Optimize when 'e' is 'not' something, inverting the condition ** and removing the 'not'. */ static int jumponcond (FuncState *fs, expdesc *e, int cond) { if (e->k == VRELOCABLE) { Instruction ie = getinstruction(fs, e); if (GET_OPCODE(ie) == OP_NOT) { fs->pc--; /* remove previous OP_NOT */ return condjump(fs, OP_TEST, GETARG_B(ie), 0, !cond); } /* else go through */ } discharge2anyreg(fs, e); freeexp(fs, e); return condjump(fs, OP_TESTSET, NO_REG, e->u.info, cond); } /* ** Emit code to go through if 'e' is true, jump otherwise. */ void luaK_goiftrue (FuncState *fs, expdesc *e) { int pc; /* pc of new jump */ luaK_dischargevars(fs, e); switch (e->k) { case VJMP: { /* condition? */ negatecondition(fs, e); /* jump when it is false */ pc = e->u.info; /* save jump position */ break; } case VK: case VKFLT: case VKINT: case VTRUE: { pc = NO_JUMP; /* always true; do nothing */ break; } default: { pc = jumponcond(fs, e, 0); /* jump when false */ break; } } luaK_concat(fs, &e->f, pc); /* insert new jump in false list */ luaK_patchtohere(fs, e->t); /* true list jumps to here (to go through) */ e->t = NO_JUMP; } /* ** Emit code to go through if 'e' is false, jump otherwise. */ void luaK_goiffalse (FuncState *fs, expdesc *e) { int pc; /* pc of new jump */ luaK_dischargevars(fs, e); switch (e->k) { case VJMP: { pc = e->u.info; /* already jump if true */ break; } case VNIL: case VFALSE: { pc = NO_JUMP; /* always false; do nothing */ break; } default: { pc = jumponcond(fs, e, 1); /* jump if true */ break; } } luaK_concat(fs, &e->t, pc); /* insert new jump in 't' list */ luaK_patchtohere(fs, e->f); /* false list jumps to here (to go through) */ e->f = NO_JUMP; } /* ** Code 'not e', doing constant folding. */ static void codenot (FuncState *fs, expdesc *e) { luaK_dischargevars(fs, e); switch (e->k) { case VNIL: case VFALSE: { e->k = VTRUE; /* true == not nil == not false */ break; } case VK: case VKFLT: case VKINT: case VTRUE: { e->k = VFALSE; /* false == not "x" == not 0.5 == not 1 == not true */ break; } case VJMP: { negatecondition(fs, e); break; } case VRELOCABLE: case VNONRELOC: { discharge2anyreg(fs, e); freeexp(fs, e); e->u.info = luaK_codeABC(fs, OP_NOT, 0, e->u.info, 0); e->k = VRELOCABLE; break; } default: lua_assert(0); /* cannot happen */ } /* interchange true and false lists */ { int temp = e->f; e->f = e->t; e->t = temp; } removevalues(fs, e->f); /* values are useless when negated */ removevalues(fs, e->t); } /* ** Create expression 't[k]'. 't' must have its final result already in a ** register or upvalue. */ void luaK_indexed (FuncState *fs, expdesc *t, expdesc *k) { lua_assert(!hasjumps(t) && (vkisinreg(t->k) || t->k == VUPVAL)); t->u.ind.t = t->u.info; /* register or upvalue index */ t->u.ind.idx = luaK_exp2RK(fs, k); /* R/K index for key */ t->u.ind.vt = (t->k == VUPVAL) ? VUPVAL : VLOCAL; t->k = VINDEXED; } /* ** Return false if folding can raise an error. ** Bitwise operations need operands convertible to integers; division ** operations cannot have 0 as divisor. */ static int validop (int op, TValue *v1, TValue *v2) { switch (op) { case LUA_OPBAND: case LUA_OPBOR: case LUA_OPBXOR: case LUA_OPSHL: case LUA_OPSHR: case LUA_OPBNOT: { /* conversion errors */ lua_Integer i; return (tointeger(v1, &i) && tointeger(v2, &i)); } case LUA_OPDIV: case LUA_OPIDIV: case LUA_OPMOD: /* division by 0 */ return (nvalue(v2) != 0); default: return 1; /* everything else is valid */ } } /* ** Try to "constant-fold" an operation; return 1 iff successful. ** (In this case, 'e1' has the final result.) */ static int constfolding (FuncState *fs, int op, expdesc *e1, const expdesc *e2) { TValue v1, v2, res; if (!tonumeral(e1, &v1) || !tonumeral(e2, &v2) || !validop(op, &v1, &v2)) return 0; /* non-numeric operands or not safe to fold */ luaO_arith(fs->ls->L, op, &v1, &v2, &res); /* does operation */ if (ttisinteger(&res)) { e1->k = VKINT; e1->u.ival = ivalue(&res); } else { /* folds neither NaN nor 0.0 (to avoid problems with -0.0) */ lua_Number n = fltvalue(&res); if (luai_numisnan(n) || n == 0) return 0; e1->k = VKFLT; e1->u.nval = n; } return 1; } /* ** Emit code for unary expressions that "produce values" ** (everything but 'not'). ** Expression to produce final result will be encoded in 'e'. */ static void codeunexpval (FuncState *fs, OpCode op, expdesc *e, int line) { int r = luaK_exp2anyreg(fs, e); /* opcodes operate only on registers */ freeexp(fs, e); e->u.info = luaK_codeABC(fs, op, 0, r, 0); /* generate opcode */ e->k = VRELOCABLE; /* all those operations are relocatable */ luaK_fixline(fs, line); } /* ** Emit code for binary expressions that "produce values" ** (everything but logical operators 'and'/'or' and comparison ** operators). ** Expression to produce final result will be encoded in 'e1'. ** Because 'luaK_exp2RK' can free registers, its calls must be ** in "stack order" (that is, first on 'e2', which may have more ** recent registers to be released). */ static void codebinexpval (FuncState *fs, OpCode op, expdesc *e1, expdesc *e2, int line) { int rk2 = luaK_exp2RK(fs, e2); /* both operands are "RK" */ int rk1 = luaK_exp2RK(fs, e1); freeexps(fs, e1, e2); e1->u.info = luaK_codeABC(fs, op, 0, rk1, rk2); /* generate opcode */ e1->k = VRELOCABLE; /* all those operations are relocatable */ luaK_fixline(fs, line); } /* ** Emit code for comparisons. ** 'e1' was already put in R/K form by 'luaK_infix'. */ static void codecomp (FuncState *fs, BinOpr opr, expdesc *e1, expdesc *e2) { int rk1 = (e1->k == VK) ? RKASK(e1->u.info) : check_exp(e1->k == VNONRELOC, e1->u.info); int rk2 = luaK_exp2RK(fs, e2); freeexps(fs, e1, e2); switch (opr) { case OPR_NE: { /* '(a ~= b)' ==> 'not (a == b)' */ e1->u.info = condjump(fs, OP_EQ, 0, rk1, rk2); break; } case OPR_GT: case OPR_GE: { /* '(a > b)' ==> '(b < a)'; '(a >= b)' ==> '(b <= a)' */ OpCode op = cast(OpCode, (opr - OPR_NE) + OP_EQ); e1->u.info = condjump(fs, op, 1, rk2, rk1); /* invert operands */ break; } default: { /* '==', '<', '<=' use their own opcodes */ OpCode op = cast(OpCode, (opr - OPR_EQ) + OP_EQ); e1->u.info = condjump(fs, op, 1, rk1, rk2); break; } } e1->k = VJMP; } /* ** Apply prefix operation 'op' to expression 'e'. */ void luaK_prefix (FuncState *fs, UnOpr op, expdesc *e, int line) { static const expdesc ef = {VKINT, {0}, NO_JUMP, NO_JUMP}; switch (op) { case OPR_MINUS: case OPR_BNOT: /* use 'ef' as fake 2nd operand */ if (constfolding(fs, op + LUA_OPUNM, e, &ef)) break; /* FALLTHROUGH */ case OPR_LEN: codeunexpval(fs, cast(OpCode, op + OP_UNM), e, line); break; case OPR_NOT: codenot(fs, e); break; default: lua_assert(0); } } /* ** Process 1st operand 'v' of binary operation 'op' before reading ** 2nd operand. */ void luaK_infix (FuncState *fs, BinOpr op, expdesc *v) { switch (op) { case OPR_AND: { luaK_goiftrue(fs, v); /* go ahead only if 'v' is true */ break; } case OPR_OR: { luaK_goiffalse(fs, v); /* go ahead only if 'v' is false */ break; } case OPR_CONCAT: { luaK_exp2nextreg(fs, v); /* operand must be on the 'stack' */ break; } case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV: case OPR_IDIV: case OPR_MOD: case OPR_POW: case OPR_BAND: case OPR_BOR: case OPR_BXOR: case OPR_SHL: case OPR_SHR: { if (!tonumeral(v, NULL)) luaK_exp2RK(fs, v); /* else keep numeral, which may be folded with 2nd operand */ break; } default: { luaK_exp2RK(fs, v); break; } } } /* ** Finalize code for binary operation, after reading 2nd operand. ** For '(a .. b .. c)' (which is '(a .. (b .. c))', because ** concatenation is right associative), merge second CONCAT into first ** one. */ void luaK_posfix (FuncState *fs, BinOpr op, expdesc *e1, expdesc *e2, int line) { switch (op) { case OPR_AND: { lua_assert(e1->t == NO_JUMP); /* list closed by 'luK_infix' */ luaK_dischargevars(fs, e2); luaK_concat(fs, &e2->f, e1->f); *e1 = *e2; break; } case OPR_OR: { lua_assert(e1->f == NO_JUMP); /* list closed by 'luK_infix' */ luaK_dischargevars(fs, e2); luaK_concat(fs, &e2->t, e1->t); *e1 = *e2; break; } case OPR_CONCAT: { luaK_exp2val(fs, e2); if (e2->k == VRELOCABLE && GET_OPCODE(getinstruction(fs, e2)) == OP_CONCAT) { lua_assert(e1->u.info == GETARG_B(getinstruction(fs, e2))-1); freeexp(fs, e1); SETARG_B(getinstruction(fs, e2), e1->u.info); e1->k = VRELOCABLE; e1->u.info = e2->u.info; } else { luaK_exp2nextreg(fs, e2); /* operand must be on the 'stack' */ codebinexpval(fs, OP_CONCAT, e1, e2, line); } break; } case OPR_ADD: case OPR_SUB: case OPR_MUL: case OPR_DIV: case OPR_IDIV: case OPR_MOD: case OPR_POW: case OPR_BAND: case OPR_BOR: case OPR_BXOR: case OPR_SHL: case OPR_SHR: { if (!constfolding(fs, op + LUA_OPADD, e1, e2)) codebinexpval(fs, cast(OpCode, op + OP_ADD), e1, e2, line); break; } case OPR_EQ: case OPR_LT: case OPR_LE: case OPR_NE: case OPR_GT: case OPR_GE: { codecomp(fs, op, e1, e2); break; } default: lua_assert(0); } } /* ** Change line information associated with current position. */ void luaK_fixline (FuncState *fs, int line) { fs->f->lineinfo[fs->pc - 1] = line; } /* ** Emit a SETLIST instruction. ** 'base' is register that keeps table; ** 'nelems' is #table plus those to be stored now; ** 'tostore' is number of values (in registers 'base + 1',...) to add to ** table (or LUA_MULTRET to add up to stack top). */ void luaK_setlist (FuncState *fs, int base, int nelems, int tostore) { int c = (nelems - 1)/LFIELDS_PER_FLUSH + 1; int b = (tostore == LUA_MULTRET) ? 0 : tostore; lua_assert(tostore != 0 && tostore <= LFIELDS_PER_FLUSH); if (c <= MAXARG_C) luaK_codeABC(fs, OP_SETLIST, base, b, c); else if (c <= MAXARG_Ax) { luaK_codeABC(fs, OP_SETLIST, base, b, 0); codeextraarg(fs, c); } else luaX_syntaxerror(fs->ls, "constructor too long"); fs->freereg = base + 1; /* free registers with list values */ }